CHARACTERIZATION OF A COMBINATORIAL PHAGE DISPLAY LIBRARY DERIVED FROM A CCHD PATIENT

GRIPPO VANINA; MAHLER E; LEVIN MJ

Congreso; XXXIX Reunion Anual de la Sociedad Argentina de Investigaciones en Bioquimica y Biologia Molecular; 2003

Chronic Chagas´ Heart Disease (cChHD) patients present antibodies against the Trypanosoma cruzi ribosomal P proteins (anti-P Abs) which are able to stimulate cardiovascular receptors. To better understand this complex response we constructed a Fab combinatorial library from bone marrow from a cChHD patient. The size of the library was  >1 x 108 cfu/mg. The phage library was panned against T.cruzi lysate and P proteins obtaining specific clones (T and P  respectively). The reactivity profile of anti-T Fab resembled the one observed for the serum of patient. Furthermore, we analyzed the repertoire and distribution of rearranged VH genes to elucidate similarities to and differences from autoimmune processes. We sequenced 93 clones from the unselected library, 36 anti-T and 56 anti-P clones. The VH family usage in the library and amongst the T-clones was not different than in healthy adult repertoire. However, there was a VH4  overrepresentation in P clones, possibly indicating an autoimmune component in the anti-P response. The CDR3 regions were significantly longer in the unselected and panned libraries than in healthy repertoire. Analyzed Abs present a high degree of somatic mutation. In this study, we report the characterization of the first combinatorial antibody library derived from a patient with cChHD and an analysis of its repertoire. This approach may help to better understand the humoral response against the parasite and to obtain human monoclonal Abs against different T. cruzi  antigens.